Clinical trials play an important role in the advancement of medical care. Over $ 6 billion are spent annually on clinical research. Clinical protocols are increasingly complex. Data inaccuracy in the early phase of a new research trial is a commonly known, but incompletely described component of clinical research. These errors are likely a result of coordinators lacking mastery of the knowledge, skills, and attitudes needed to properly conduct the research protocol. Most historical studies on research integrity consider ethical issues associated with clinical trials and protocol design. Little attention has been paid to issues of data integrity and patient safety in the proper conduct of a trial. Modern theory stresses the importance of interactivity in learning. Simulation is considered a top methodology for learning complex behaviors. The use of high-fidelity patient simulation in clinical research training is expected to improve the coordinator's acquisition of the knowledge, skills, and behaviors needed to properly perform a protocol. Enhanced coordinator performance is expected to lead to improved data integrity and heightened patient safety. Recent efforts in our laboratory demonstrate marked improvement in coordinator confidence following high-fidelity simulation training (in their ability to properly conduct the trial). Objective measures of coordinator competence are now needed to properly assess the effects of simulation training on research integrity. One objective method of assessing coordinator competence is through queries of errors in the protocol's data record. The goal of this study is to first define a taxonomy to categorize and quantify clinical research errors rates in a reproducible fashion. We will then apply our taxonomy to define baseline error rates and the learning curve in a recently completed NIH funded multi-center trial. This proposal is intended to provide the groundwork for later studies investigating the impact of high-fidelity simulation on the competent performance of clinical trials.